Azo dyestuffs



Patented June 6, 1939 UNITED STATES AZO DYESTUFFS Arthur Howard Knight, Blackley, Manchester,

England, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain No Drawing. Application March 18, 1938, Serial No. 196,793. In Great Britain March 23, 1937 3 Claims.

. The present invention relates to the manufacture of water-soluble monoazo dyestuffs and to their use for colouring acetate artificial silk.

This invention has as an object to devise a method of manufacturing new water-soluble monoazo dyestuffs. vide new water-soluble monoaz'o dyestuffs. 'A still further object is to devise a new method of colouring acetate artificial silk. ,A still further object is to provide acetate artificial silk in new colours. Further objects will appear hereinafter. These objects are accomplished by the following invention.

I have found that I can manufacture new dyestufis by coupling a diazotised para-nitroamine of the benzene or naphthalene series, devoid of sulphonic and carboxylic acid groups, with the sulphuric ester of a substituted Py-tetrahydro-3- hydroxyquinoline of the general formula I CH-OH Where X represents hydrogen, halogen or alkyl and Y represents alkyl or aralkyl.

Alternatively, I can manufacture the said new dyestuffs by treating the water-insoluble dyestufis obtained by coupling a diazotised para-nitroamine of the benzene or naphthalene series, devoid of sulphonic and carboxylic acid groups, with a substituted Py-tetrahydro-3 hydroxyquin oline of the general formula CH-OH where X and Y have the same significance as before, with an agent adapted to form their sulphuric esters, such as,for example, sulphuric acid.

Also according to the invention I can apply the new dyestuffs to the colouring of acetate .artificial silk.

The coupling components employed according to the embodiment of the invention first specified above may be prepared by treating the appropriate Py-tetrahydro-3-hydroxyquinoline derivatives, as above defined, with an agent adapted to form their sulphuric esters such as, for example, chlorosulphonic acidor sulphuric acid.

. The invention is illustrated, but not limited, by the following examples in which the partsare by weight. a 1

A further objectis to pro Example 1 tained is added to a cooled aqueous solution of i 27.2 parts of the sulphuric ester of 1-ethyl-3-hydroxy-l-methyl-Py-tetrahydroquinoline containing sodium carbonate in sufficient amount to ensure that the solution remains alkaline to litmus after the addition of the diazo solution is complete. 10% of common salt (weight for volume) is then added to precipitate the dyestuff, which is filtered off and .dried. It is soluble in warm water and produces on acetate artificial silk crimsonred shades when applied from a neutral dyebath containing 1% common salt. It has the probable formula 19 parts of 2:4-dinitroaniline-are added to a solution of nitrosyl sulphuric acid, obtained by adding 6.9 parts of dried sodium nitrite to parts of concentrated sulphuric acid, and the liquid is'stirred until the amine is dissolved. The resulting solution is poured upon ice and the aqueous solution so obtained is filtered. The filtered diazo solution is then added with stirring to an aqueous solution of 29.4 parts of the sodium salt Ki of the sulphuric ester of 1-ethyl-3-hydroxy-7- 'methyl-Py-tetrahydroquinoline. If desired, a buffering agent, such as sodium, acetate, is added to facilitate coupling. When coupling is complete the dyestufi is filtered off and washed with Water to remove sulphuric acid. The dyestulf paste is suspended in 600 parts of water, and converted to its sodium salt by adding sodium carbonate until the solution is alkaline to litmus.

Common salt is added, if necessary, to precipitate Example 3 13.8 parts of p-nitroaniline are diazotised and the diazo solution is added to a cooled aqueous solution of 25.8 parts of the sulphuric ester of 1- ethyl-3-hydroXy-Py-tetrahydroquinoline containing excess of sodium carbonate. The new dyestufi so obtained is isolated by the addition of 5% common salt (weight for volume), filtering and drying. It dissolves in hot water and yields red shades on acetate artificial silk when applied from a neutral dyebath containing 1% common salt. It has the probable formula 18.3 parts of 2:4-dinitroaniline are diazotised dried. It dissolves in warm water and dyes acetate artificial silk in bluish-violet shades when applied from a dyebath containing 1% common salt. It has the probable formula 21.75 parts of 6-ch1oro-2:4-dinitroaniline are gradually added to a solution of 6.9 parts of sodium nitrite in parts of concentrated sulphuric acid. The resulting solution is warmed to 50-55 C., which temperature is maintained for two hours. Thesolution is then cooled to 20 20-25 C; and added slowly to a solution of 32.1 parts of the sodium salt of the sulphuric ester of 1-n butyl-3-hydroxy-7-methylPy-tetrahydroquinoline and 13.6 parts of crystallised sodium acetate in 500 parts of water containing ice. Simultaneously 40% sodium hydroxide solution is added at such a rate that the coupling medium remains only faintly acid to Congo Red paper. During the couplim ice is added as necessary so that the temperature does not rise above 0 C.

When coupling is complete the suspension of the new dy'estuff so obtained is rendered alkaline with caustic soda, the mixture stirred for some time to complete the conversion of the dyestufi 35 to its sodium salt, and the latter filtered off and dried. It dyes acetate artificial silk in navy blue shades when applied from a dyebath containing 1% salt. It has the following probable formula by the aid of nitrosyl sulphuric acid in conoen- 0.11 40 trated sulphuric acid solution in the known way and the aqueousv solution of the diazo compound 01 CHF obtained by pouring the concentrated sulphuric E acid solution on to ice is coupled with 21.9 parts NOT N: cn0o-Na of 1-n-butyl-3-hydroxy-7-methyl-Py-tetrahydro- Q l 45 quinoline dissolved in dilute aqueous hydrochloric N02 acid. The resulting insoluble monoazo compound after being. filtered off and washed with water is p The invention is further illustrated by the dyere-suspended in water, the suspension rendered stuffs of the following table:

figy Diazo component Coupling component i gf gg'i g g 7 2-ch1oro- 4-nitroaniline l-ethyl-3-hydroxy-Py-tetrahydro-quinolinesulphuricester. Very bluish red.

2-cyano-4-nitroani1ine l-ethyl-3-hydroxy-Py-tetrahydro-quinolinesulphuricester. Reddish violet. 55 2:4-dinitro-aniline Bluish violet.

2:G-dichlorol-nitroaniline Orange brown. 4-nitro-l-naphthylamine do Bluish red.

2:4-dinitro-anilino l-n -butyl-3-hydroxy-7-1nethyl-Py-tetrahydroquinoline Bluish violet.

sulphuric ester. 2-chloro-4-nitroaniline do Reddish violet. 2-cyano-4-nitroaniline do Bluish violet. 0

2:4-dinitro-aniline 1-n-butyl-3-hydroxy-7-chloro-Py-tetra-hydroquinoline Reddish violet.

sulphuric ester.

alkaline and the monoazo compound filtered off, This invention is a valuable advance in the dried and powdered. The powdered insoluble art, giving new water soluble dyes which possess 35 monoazo compound is then added slowly during good aifinity for acetate artificial silk which they about one hour to 150 parts of concentrated suldye in red, brown, violet and blue shades. They phuric acid. The sulphuric acid solution so obare also eminently suitable for the printing of tained is stirred for a further 45 hours and then acetate artificial silk. poured on to ice. The new sulphuric ester dye- As many apparently widely difierent embodistufi, which is precipitated, is filtered off, rements Of this invention may be made without suspended in 500 parts of water containing 50 departing-from the spirit and scope thereof, it parts of common salt and the suspension rento be understood that I do not limit myself dered alkaline with sodium carbonate. The new to the specific embodiments thereof, except as dyestufi (as sodium salt) is then filtered off and defined in the appended claims. 45

in which aryl is a radical from the group consisting of para-nitro-amines of the benzene and naphthalene series free from water-solubilizing groups, X is one of the group consisting of hydrogen, halogen, and alkyl, and Y is one of the 7 group consisting of alkyl and aralkyl.

.2. The compound represented by the formula:

3 The process which comprises diazotizing one of the groups consisting of the para-nitro-amines of the benzene and naphthalene series devoid of sulfonic and carboxylic acid groups, and coupling it with the sulfuric ester of a Py-tetrahydro-3-hydroxy-quino1ine of the formula:

where X represents one of the group consisting of hydrogen, halogen or alkyl, and Y represents one of the group consisting of alkyl or aralkyl.

ARTHUR HOWARD KNIGHT. 

